Controllable pitch propeller



May 5, 1942. c. KELLER 2,282,297

CONTROLLABLE PITCH PROPELLER Filed March 30, 1958 2 Sheets-Sheet l /llllll Il l lll\\\\\\\\ n 4 41%/ B f//y S5 Patented May 5, 1942 UNITED STATE-s PATENT OFFICE 2,282,297 CONTROLLABLE PITCH PROPELLER -Curt Keller,- Zurich, Switzerland, assigner to Escher Wyss Maschineni'abriken Aktiengesellschaft, Zurich, Switzerland Application March 30, 1938, Serial No. 198,844

- In Switzerland April 1, 1937 8 Claims.

My invention relates to controllable pitch propellers and more particularly to the hydraulic control of the propeller blades, especially of the kindformed with a central opening extending in the direction of the axis of rotation of the propeller.

It is one of the objects of my invention to provideblade controlling means which, whilst enabling the blades to be continuously adjusted within a large range of adjustment, automatically locks mechanically the blades whenever the iluid pressure required for adjustment should fail, whereupon the propeller can continue to work like one with ilxed blades.

In order that this object be attained, controlling mechanism according to the present invention comprises, in addition to the blade adjusting means proper, auxiliary means held by the liquid, which operates the adjusting means, against the action of an auxiliary force in a position from which they move automatically into the position wherein they lock mechanically the adjusting means as soon as the pressure of the liquid falls below a xed minimum value.

In the drawings ailixed to this specification and forming part thereof an embodiment of my invention is illustrated diagrammatically by way of example.

In the drawings Fig 1 is a section on the line I-I in Fig. 2,

Fig. 2 being a section on the line II-II, and

Fig. 3 a section on the line III-III in Fig. 1, while Figs 4 to 6 illustrate this embodiment on a larger scale.

Fig 4 being an axial longitudinal section through a portion of the propeller.

Fig. 5 is a section on the line X-X of Fig. 4, and

Fig. 6 is a section on the line XI-XI of Fig. 5.

Referring to the drawings 50 is a movable cylinder. The fixed piston, relatively to which the cylinder 50 can be displaced, consists of two parts 5|, 52. The axial movement of the cylinder 50 is brought about by supplying a liquid under pressure from a source l to one or the other of two chambers 55, .56 formed by the cylinder 50 and the piston 5|, 52. The cylinder 55 is formed on the inside with circular grooves 53. The means for locking the cylinder 50 comprise three auxiliary pistons 54 mounted displaceably within the piston 52, each piston .54 deilining, together with the piston part 5|, a space 58 supplied with liquid under pressure from the source 18 to which can also be connected the two spaces 55, 58 above and below the piston (ci. 17o-.163)

5|, 52. When liquid under pressure is supplied to the space 58, the corresponding auxiliary piston 54 is moved against the action of a spring 59 into one of its two end positions. 60 (Fig. 5) is an auxiliary distributing valve controlling the supply and exhaust ofliquid under pressure to the chambers 58. l

On each side of each auxiliary piston 54 is arranged a pawl 6|, -which is displaceable between the piston parts 5|. 52. The pawls 6| are formed with teeth 53 (Fig. 5) the cross-section of which corresponds to that of thecircular grooves 53 of the cylinder 50. Each pawl 5| is pivoted to a pin 52 (Figs. 2, 4 and 5), the pins 62 being fixed inside the piston parts 5|, 52, and is connected through a link 84 to a movable cross-head 51 adapted to be displaced transversely within the correlated auxiliary piston 54. .The teeth 53 of the diiferent pawls 6| are displaced, in respect to one another, in such a manner, in the direction of the axis of the cylinder 50, that only two diametrically opposite pawls 6| can engage at the same time in the grooves 53 of the cylinder 50.

The axial displacement of the cylinder 50 is transmitted by pins 55 (Figs. 4 and 5) mounted on a ring 66 to connecting rods 68' for adjusting the'blades 12, each of which is mounted in a socket bearing a pin 89 which is connected by means of the rod 58 with a pin 85 on ring 56. Ring 66 is fixed to cylinder 50 by means of a nut 6l'. Here also cylinder 5|) is prevented, by means arranged on the hub (not shown), from rotating.

The device operates as follows: In'Fig. 4 the auxiliary distributing valve 6o is shown in its middle position. If it be assumed that liquid under pressure shall be fed to the chamber 55 cf the adjusting cylinder 50, in which case the control valve Illll1 (Fig. 1) of the-control device |05 has been so adjusted by the centrifugal governor 91 that liquid can enter the conduit 14 (Figs. 4 and 5) of the hollow shaft 94, the liquid will ow through an aperture 84 in the hollow shaft 84 into the annular space 95 (Fig. 4) in front of the control valve which is freely dsplaceable. valve 60 is now shifted into its rear end position, in which the aperture is connected through the annular space with another aperture 85 in the hollow shaft 94, which leads to a conduit 11 extending in the longitudinal direction of the shaft and communicating through a conduit 8| in the piston 5| with the space 58. The auxiliary pistons 54 are therefore shifted, counter to the action of the springs 58,' to the rear, lwhereby the teeth 63 of all pawls 5| are disengaged from the notches 53 of the main cylinder 50. Each auxil- `mined pawls 6| are caused to engage in the grooves 53 iary cylinder 54 now uncovers a conduit 82- in the piston 5|, which conduit communicates with a conduit 18, leading to an aperture 88 in the hollow shaft 94. In the rear end position of the control valve 60 the aperture 88 is connected through an annular groove in the value 80 with an aperture 81 of the hollow shaft 94, which aperture is further connected through the longitudinal conduit 19 and an aperture 88 with the chamber 55 of the main adjustinmcylinder 58.

. The liquid under pressure which enters the chamber 55, now shifts the cylinder 5|) forwards and thereby causes the blades 12 of the propeller to be adjusted by means of the parts 59, 88, 85, 66. During this movement of the adjusting cylinder 58 the chamber 58 must be enabled to discharge liquid; this can be done through an aperture 93 in the hollow shaft 94, a conduit 18 and an aperture 89, which now communicates by way of an annular groove 891 of th'e control valve 80 and an aperture 90 with the conduit 15 extending longitudinally of the shaft 94. This conduit 15 is connectedat this moment with the exhaust pipe |882 (Fig. 1) by the control valve |0|l1 of the controldevice |00.

If the propeller blades 12 shall be adjusted in the opposite direction, the value Illll1 of the control device ||l0 is shifted bythe centrifugal. governor 91 into a position in which liquid under pressure may enter the conduit 15 in the hollow shaft 94. Through an aperture 92 in the shaft communicating `with conduit 15 liquid now enters the annular space 96 (Fig. 4) to the rear of the valve 60, whereby this latter is now shifted into its forward end position. Liquid under pressure may now flow from the annular space 96 through the aperture 9| into the longitudinal conduit 11 tf sha-t 94 and from this conduit through conduit 8| of piston 5| into the space 58 between the auxiliary piston 54 and piston 5|. AIn the meantime the valve 68 has covered the apertures 85 and 98. The piston 54 is now caused to move to the rear counter to the action of the springs 59, whereby the teeth 63 of the locking members 6| are disengaged from the notches 53 of cylinder`50. The conduit t2 in the piston 5| is now uncovered by the piston 54, so that liquid under pressure can also enter the chamber 56 through conduits 82 and 18, apertures 88, 89, conduit 16 and aperture t3. At the same time the chamber :.5 is connected by way of the aperture 80, condu-t 19, apertures 81, 86 and conduit 14 with the exhaust lill)2 of the control device I0il. The adjusting cylinder 50 is ncw free to move towards the rear and to thereby adjust the propeller blades to' the desired position.

In Fig. 5 the pawls A and B are shown in the position in which they engage in the grooves 53 whilst the other four pawls '6| are shown in the position in which they rest on the projecting parts of the grooves 53, without however engaging the latter. In this manner it is possible to lock the cylinder 50 in a position which very accurately corresponds to that required; consequently, it is also possible to accurately hold the blades of the propeller accurately in a predeterposition. Two diametrically opposed of the cylinder 50 as soon as the pressure exerted by the liquid supplied to the spaces 58 correlated to said pawls is lower than the pressure exerted by the spring 59 on the piston 54. The two pawls 6| caused to engage in the cylinder 58, then prevent any further axial displacement of the latter, whereby the means (not shown) for shown and described for obvious modifications will occur to a person skilled in thev art.

I claim: v

1. Controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes,'means displaceable by the action of a hydraulic pressure medium and comprising a piston arranged coaxially to said hub and a cylinder axially displaceablerelative to said piston for adjusting said blades,and means acted upon by the same hydraulic pressure medium and adapted to instantly lock mechanically said cylinder and through it also the blades in their actual positions, whenever and as long as the hydraulic pressure drops, and remains, below a predetermined value, said locking means controlling moreover the admission of the hydraulic pressure medium to one or the other of two chambers in the cylinder on opposite sides of said piston in such a way that a supply of pressure medium can only occur after said mechanical locking means have released the cylinder.

2. controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydrauLc pressure medium comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said pisten for adjusting said blades, means acted upon by the same hydraulic pressure medium and adapted to instantly lock mechanically said cylinder and thereby also said blades in their actual positions, whenever, and as long as, the hydraulic pressure drops, and remains, below a predetermined value, and means for preventing angular movement of said axially displaceable cylinder relative to said hub, said locking means controlling moveo'v er the admission of the hydraulic pressure medium to either one of two chambers in the cylinder on both sides of said piston in such a way that a supply of pressure medium can only occur alter said mechanical lockin means have released the cylinder.

3; Controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydraulic pressure medium comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston for adjusting said blades, other displaceable means adapted to be acted upon by the same hydraulic pressure medium, locking members operatively connected to said other displaceable means and located within said displaceable cylinder, and means on said cylinder enabling said locking members to instantly .lock mechanically said cylinder in its actual position whenever, and as long as, the hydraulic pressure drops and remains below a predetermined value, said other in saiddisplaceable mechanical locking members have released thel Cylinder.'

4. controllable pitch combination, a hub, a

propeller comprising in plurality of blades arranged'on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydraulic pressure medium comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston for adjusting said blades, auxiliary pistons displaceable within said cylinder and adapted to be acted upon by the same hydraulic pressure as the cylinder, locking members operatively connected to said auxiliary pistons and located withcylinder, and means on said cylinder enabling said locking members to instantly lock mechanically said cylinder in its actual position whenever, and as long as, the hydraulic pressure drops, and remains, below a predetermined value, said auxiliary pistons controlling. the admission of the hydraulic pressure medium to one or the other of two chambers in the cylinder on both sides of said piston in such a way that a supply of pressure medium can only occur after said mechanical locking members have released the cylinder.

5. controllable combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action or a hydraulic pressure medium and comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston for adjusting said blades, other displaceable means adapted to be acted upon by the same hydraulic pressure medium, and toothed pawls operatively connected'to said other displaceable means and located within said displaceable cylinder, which cylinder is formed with grooves on its inner circumference serving to cooperate with said toothed pawls to instantly lock said cylinder in its actual position whenever the hydraulic pressure drops below a predetermined value.

6. controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydraulic pressure medium and comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston, for adjusting said blade other displaceable means adapted to be acted upon by the same hydraulic pressure medium, and toothed pawls operatively connected to said pitch propeller comprising in' other displaceable means, said pawls being located within said displaceable cylinder, which cylinder is formed with grooves on its inner circumference, ,the teeth on one of said pawls being so staggered relative to the teeth adapted t0 be acted on another pawl in the said cylinder that only the teeth on diametrically opposite pawls can engage in the grooves of the cylinder to instantly lock said cylinder in its actual position whenever the hydraulic pressure drops below a predetermined value.

7. controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydraulic pressure medium and comprising a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston for adjusting said blades, auxiliary pistons movably -arranged within said displaceable cylinder and adapted to be acted upon by the same hydraulic pressure medium, springs acting on the auxiliary pistons in a direction opposite to that of the hydraulic pressure medium, a cross-head in connection with each auxiliary piston and movable transversely therein, locking members operatively connected to said cross-heads and located within said displaceable cylinder, and means on said cylinder enabling said locking members to instantly lock said cylinder in its actual position whenever the spring pressure acting on the auxiliary pistons ls greater than the prevailing hydraulic pressure, said auxiliary pistons controlling the admission of the hydraulic pressure medium to the one or the other of two chambers in the displaceable cylinder on both sides o1 said piston in such away that `a supply of medium can only'occur after that said locking members have released the cylindeny' 8. controllable pitch propeller comprising in combination, a hub, a plurality of blades arranged on said hub for adjustment about their longitudinal axes, means displaceable by the action of a hydraulic pressure medium and comprisingl a piston arranged coaxially to said hub and a cylinder axially displaceable relative to said piston for. ad-

justing said blades, a number oi.' auxiliary means upon in succession by the same hydraulic pressure medium, locking members located within said displaceable cylinder and operatively connected to said auxiliary means by which they can besuccessively disengaged and means on said cylinder enabling said locking members to instantly lock said cylinder in its actual position whenever the hydraulic pressure drops below a predetermined value.

cUR'r direction of the axis of i 

